Class 8, 9 Spring ᯓᡣ𐭩

Question 1

What is joint probability?

Answer 1

The probability of getting the variables/processes/outcomes A or B

‘Or’ means and/or.

Question 2

What is the probability for independent variables A and B?

Answer 2

The probability for events from independent variables/processes/outcomes A and B.

Question 3

What is the probability for dependent variables A and B?

Answer 3

The probability of outcome A, given knowledge about B.

Question 4

What percentage of people like In-N-Out best?

Answer 4

68% of people like In-N-Out best.

Question 5

What is the percentage of women who prefer In-N-Out?

Answer 5

72% of women prefer In-N-Out.

Question 6

What is the percentage of men who prefer In-N-Out?

Answer 6

65% of men prefer In-N-Out.

Question 7

What are descriptive statistics?

Answer 7

Methods used to summarize or describe observations in a particular sample.

Question 8

What are inferential statistics?

Answer 8

Using observations as a basis for making estimates or predictions about a situation that has not yet been observed.

Question 9

Give an example of descriptive statistics.

Answer 9

Calculating the average height of a whole classroom.

Question 10

Give an example of inferential statistics.

Answer 10

Extrapolating the average height of one 5th grade class to predict another.

Question 11

What is a population in statistics?

Answer 11

All the cases or situations that the statistician wants their inferences to apply to.

Question 12

What is a sample?

Answer 12

A relatively small selection from within a population.

Question 13

What is a simple random sample?

Answer 13

An approach where each element of the population is likely to be selected.

Question 14

What does inferential statistics focus on?

Answer 14

Making estimates and inferences about a wider population.

Question 15

What is random error?

Answer 15

Describes how much an estimate will tend to vary from one sample to the next.

Question 16

What is the symbol for sample size?

Answer 16

n.

Question 17

What is the symbol for population size?

Answer 17

N.

Question 18

True or False: Random error has a preferred direction away from the mean.

Answer 18

False.

Question 19

What is systematic bias?

Answer 19

The difference between survey results and population values due to incorrect measurements.

Question 20

What can cause measurement bias?

Answer 20

Incorrect measurements from broken tools or poorly trained assistants.

Question 21

What can cause sampling bias?

Answer 21

Not selecting a truly random sample representative of the larger population.

Question 22

What is the impact of random error on estimates?

Answer 22

It may be imprecise, but not inaccurate.

Question 23

What is the main way to reduce random error?

Answer 23

Collecting more data (increasing sample size).

Question 24

What is the paradox of sampling?

Answer 24

A sample is misleading unless it is representative of all natural variation in a population.

Question 25

What is a confidence interval?

Answer 25

A range of plausible values where we are likely to find the true population parameter.

Question 26

What conditions must be checked for constructing a confidence interval?

Answer 26

The sampling distribution must be normally distributed and unbiased.

Question 27

What is the central limit theorem?

Answer 27

A theorem that describes the conditions under which the sampling distribution of the sample mean will be normally distributed.

Question 28

What is a confidence interval (CI)?

Answer 28

A range of plausible values where we are likely to find the population parameter ## Footnote A confidence interval represents uncertainty in estimates and accounts for random errors.

Question 29

What is the purpose of using confidence intervals?

Answer 29

To provide a plausible range of values for the population proportion instead of just a point estimate ## Footnote This helps capture the true parameter more effectively.

Question 30

What does the sample proportion p-hat represent?

Answer 30

A single plausible value for the population proportion p ## Footnote p-hat is derived from sample data and is subject to error.

Question 31

Why is using only a point estimate compared to fishing in a murky lake with a spear?

Answer 31

Because it has a high chance of missing the true population parameter ## Footnote A point estimate does not account for variability or uncertainty.

Question 32

What is the analogy used to describe confidence intervals?

Answer 32

Fishing with a net ## Footnote A net increases the chances of capturing fish, similar to how a CI increases the likelihood of capturing the true parameter.

Question 33

What must be ensured for a confidence interval to be constructed?

Answer 33

The sampling distribution must be normally distributed and unbiased ## Footnote This is related to the conditions of the central limit theorem.

Question 34

What is the relationship between standard error and sample proportion?

Answer 34

The sample proportion has some standard error associated with it ## Footnote Standard error quantifies the variability of the sample proportion as an estimate of the population proportion.

Question 35

Fill in the blank: A confidence interval is like fishing with a net, representing a range of _______.

Answer 35

[plausible values] ## Footnote This analogy emphasizes the idea of capturing a range of potential outcomes.

Question 36

What theorem's conditions need to be checked for confidence intervals?

Answer 36

Central Limit Theorem ## Footnote This theorem ensures that the sampling distribution approaches normality as sample size increases.